判断题
A.5minB.10minC.15minD.20min
A.7~14Mpa(1000~2000lbf/in2)B.14~28MPa(2000~4000lbf/in2)C.21~35Mpa(3000~5000lbf/in2)D.28~42Mpa(4000~6000lbf/in2)